The present invention further relates to the use of these polyester mixtures.
Biodegradable polyesters such as poly(butylene adipate-co-terephthalate) (PBAT) are known from WO-A 96/015173 for example. WO-A 2010/034710 describes polyesters such as poly(butylene sebacate-co-terephthalate) (PBSeT).
Biodegradability in these references refers to compostability within the meaning of DIN EN 13432. Composting in this sense relates to industrial composters and is to be understood as meaning that a material when exposed for a defined period to defined temperature, oxygen and moisture conditions in the presence of microorganisms shall have degraded to more than 90 percent into water, carbon dioxide and biomass.
Domestic garden composting generally involves a lower temperature, so garden waste takes distinctly longer to rot down and correspondingly the degradation rates of the plastic tested are distinctly lower. ISO 20200 (2004) is an internationally standardized test for domestic garden composting.
DIN EN ISO 17556 was developed to determine ultimate aerobic biodegradability in the soil. Ultimate degradation in the soil is especially important for plastics applications in the agrisector such as, for example, mulch films, covering films, silo films, slit film tapes, wovens, nonwovens, clips, textiles, threads, fishing nets, secondary packaging, heavy-duty bags and flowerpots. Foam applications as for soil aeration must also be considered. The soil degradation performance of polyesters described in the literature is not always up to the mark.